Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to an apparatus and method for improving memory resource allocation at a base station.
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (WCDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks. High Speed Uplink Packet Access (HSUPA) is a data service offered on the uplink of UMTS networks.
In UMTS and other CDMA-based systems, “despreading” refers to processing radio signals over a radio spectrum to recover the information that has been spread or distributed over the spectrum by a transmitter using, for example, one of the CDMA-based technologies referenced above. In such systems, a base station (BS) cannot fully despread a received signal from the User Equipment (UE) until the actual spreading factor (SF) used by the UE to generate the transmitted signal is decoded from an uplink control channel, such as, for example, the Enhanced Dedicated Physical Control Channel (E-DPCCH). The BS can partially despread the received signals using a minimum SF specified by the UMTS standard and store these signal samples in a memory buffer, while it waits for the actual SF information from the UE, so it can correctly despread the signal samples. However, as the minimum SF selected by the BS to partially despread received signals is lowered, the number of signal samples that the BS has to store in its memory is correspondingly increased. This negative correlation may result in inefficient use of limited memory resources at the BS.